<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .a {
            width: 500px;
            height: 500px;
            background-color: pink;
            display: flex;
            flex-wrap: wrap;
            align-content: flex-end;
        }
        
        .b {
            width: 100px;
            height: 100px;
            background-color: red;
        }
        
        .c {
            width: 100px;
            height: 100px;
            background-color: blue;
        }
        
        .d {
            width: 100px;
            height: 100px;
            background-color: green;
        }
    </style>
</head>

<body>
    <div class="a">
        <div class="b">1</div>
        <div class="c">2</div>
        <div class="d">3</div>
        <div class="b">1</div>
        <div class="c">2</div>
        <div class="d">3</div>
        <div class="b">1</div>
        <div class="c">2</div>
        <div class="d">3</div>

    </div>

</body>

</html>